Answer:
I am known for my beautiful mane and people ride on my back. What am I?
My first is twice in apple but not once in tart. My second is in liver but not in heart. My third is in giant and also in ghost. Whole I'm best when I am toast.
Long slim and slender. Dark as homemade thunder. Keen eyes and peaked nose. Scares the Devil wherever it goes.
A close relative of ketchup that people often spread on their dog.
To you, rude would I never be, Though I flag my tongue for all to see.
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?